Semiconductor interlayer dielectric material and a semiconductor device using the same

ABSTRACT

The present invention relates to low a dielectric material essential for a next generation semiconductor with high density and high performance, and more particularly to a low dielectric material that is thermally stable and has good film-forming properties and excellent mechanical properties, a dielectric film comprising the low dielectric material, and a semiconductor device manufactured using the dielectric film. The present invention also provides an organic silicate polymer having a flexible organic bridge unit in the network prepared by the resin composition of the component (a) and the component (b), wherein component (a) is an organosilane of the formula R 1   m R 2   n SiX 4−m−n  (where each of R 1  and R 2  which may be the same or different, is a non-hydrolysable group; X is a hydrolysable group; and m and n are integers of from 0 to 3 satisfying 0≦m+n≦3) and/or a partially hydrolyzed condensate thereof and wherein component (b) is an organic bridged silane of the formula R 3   p Y 3−p Si-M-SiR 4   q Z 3−q  (where each of R 3  and R 4  which may be the same or different, is a non-hydrolysable group; each of Y and Z which may be the same or different, is a hydrolysable group; and p and q are integers of from 0 to 2) and/or a cyclic oligomer with organic bridge unit (Si-M-Si).

RELATED APPLICATIONS

[0001] This application is continuation-in-part application of copendingU.S. application Ser. No. 09/776,383, filed Feb. 2, 2001, which claimsthe benefit of U.S. Provisional Application No. 60/179,653, filed Feb.2, 2000.

FIELD OF THE INVENTION

[0002] The present invention relates to a low dielectric materialessential for a next generation semiconductor device with high densityand high performance, and more particularly to a low dielectric materialthat is thermally stable and has good film-forming properties andexcellent mechanical properties, a dielectric film comprising the same,and a semiconductor device manufactured from the dielectric film.

BACKGROUND OF THE INVENTION

[0003] The semiconductor industry is moving toward increasing devicecomplexity, requiring shrinking geometric dimensions and highercomponent integration with greater dimensional densities in integratedcircuit devices, e.g. memory and logic chips. This has led to anincrease in the number of wiring levels and a reduction in the wiringpitch to increase the wiring density. Current leading-edge logicprocessors have 6-7 levels of high density interconnect, andinterconnect line width is scheduled to decrease to 0.1 μm around theyear 2005.

[0004] As device dimensions shrink to less than 0.25 μm, the propagationdelay, crosstalk noise, and power dissipation due toresistance-capacitance (RC) coupling become significant. The smallerline dimension increases the resistivity of metal wires, and the narrowintermetal spacing increases the capacitance between the metal wires.Thus although the speed of the device will increase as the feature sizedecreases, the interconnect delay becomes the major fraction of thetotal delay and limits the overall chip performance. Accordingly, inorder to prepare a chip having high speed, a conductor having a lowresistance and a dielectric material having low dielectric constantshould be used. In addition, the use of low dielectric material canremarkably decrease the power dissipation and crosstalk noise.

[0005] Recently, several semiconductor device manufacturers have puttest products on the market that show improvement in their performanceof 20% or more, using copper wiring with high electric conductivityinstead of using the conventional aluminum wiring. Recently they shiftto use of new materials that exhibit low dielectric constantperformance, for use in interconnects. If the dielectric films betweeninterconnect layers in integrated circuit can make use of thesematerials, the effect on operating speed will be the same as that whichresulted with the switch from aluminum to copper technology. Forinstance, if the dielectric constant of the dielectric material ischanged from 4.0 to about 2.5, IC operating speed will be improved byabout 20%.

[0006] The interlayer dielectric material used in semiconductorintegrated circuit devices is predominantly SiO₂, which is generallyformed using chemical vapor deposition (CVD) or plasma enhancedtechniques and has the requisite mechanical and thermal properties towithstand various processing operations associated with semiconductormanufacturing. The relative dielectric constant of a SiO₂ materialvaries with the conditions under which a dielectric is formed; that ofsilicon thermal oxidation films, which have the lowest dielectricconstant, is on the order of 4.0. Attempts have been made to reduce thedielectric constant by introducing fluorine atoms into an inorganic filmdeposited by CVD. However, the introduction of fluorine atoms in largeamounts decreases the chemical and thermal stability, so the dielectricconstant achieved in actual practice is on the order of 3.5. Fluorinatedoxides can provide an immediate near-term solution and a shift to newtypes of insulating materials with sub-3 dielectric constant may berequired.

[0007] One class of candidates is organic polymers, some of which have adielectric constant of less than 3.0. Incorporating fluorine into suchorganic polymer is known to further lower the dielectric constant. Mostorganic polymers do not, however, possess the physico-chemicalproperties required for on-chip semiconductor insulation, particularlythermal stability and mechanical properties (sufficient to withstandback end of the line fabrication temperatures within the range of400˜450° C.). Few organic polymers are stable at temperatures greaterthan 450° C. They also have a low glass transition temperature and thuselasticity thereof remarkably decreases at high temperature, and theyhave a very high linear expansion coefficient. Since temperature risesto up to 450° C. during semiconductor IC integration and packagingprocesses, the resulting low thermal stability and elasticity and highlinear expansion coefficient can deteriorate the reliability of thedevice.

[0008] Recently in order to solve thermal stability problems of organicpolymers, the development of organic silicate polymers using a sol-gelprocess has emerged. In particular, organic SOG (Spin On Glass) has beenproposed for use as interlayer dielectrics in which the side chain of anorganic component (an alkyl group such as methyl) is bonded to thebackbone chain of a siloxane bond. While having a lower dielectricconstant, e.g., the range of about 2.7˜3.2, than conventional glasses,such materials typically have poor mechanical properties. For instance,methylsilsesquioxnane polymer experiences crack formation duringprocessing unless the film is very thin (often <1 μm).

[0009] Miller et al. have reported a method of toughening thesilsesquioxane material systems by incorporating a small amount ofpolymeric substituents such as a polyimide. A method of mixing aninorganic fine particulate powder is also known as another method forimproving the mechanical properties of organosilicates. Although varioussystems have been proposed, there remains a need for a material having asuitable low dielectric constant and appropriate physico-chemicalproperties for use as an interlayer dielectric in the future generationof IC devices.

SUMMARY OF THE INVENTION

[0010] The present invention is made in consideration of the problems ofthe prior art, and it is an object of the present invention to provide adielectric material that can make the speed of a semiconductor devicehigh, decrease power consumption thereof, and reduce crosstalk betweenmetal wiring.

[0011] It is another object of the present invention to provide anorganic silicate polymer having improved crack resistance and mechanicalstrength, a dielectric film prepared using the organic silicate polymer,a semiconductor device comprising the dielectric film, and processes forpreparing them.

[0012] In order to achieve these objects, the present invention providesan organic silicate polymer for an interlayer insulating film for asemiconductor device, which has a carbon bridge unit in the network andis prepared by a cross-linking reaction between the following component(a) and (b):

[0013] (a) organosilane of the formula R¹ _(m)R² _(n)SiX_(4−m−n) (whereeach of R¹ and R² which may be the same or different, is anon-hydrolysable group selected from hydrogen, alkyl,fluorine-containing alkyl or aryl group; X is a hydrolysable groupselected from halide, alkoxy or acyloxy; and m and n are integers offrom 0 to 3 satisfying 0≦m+n≦3), or a partially hydrolyzed condensatethereof; and

[0014] (b) organic bridged silane of the formula R³ _(p)Y_(3−p)Si-M-SiR⁴_(q)Z_(3−q) (where each of R¹ and R⁴ which may be the same or different,is non-hydrolysable group selected from hydrogen, alkyl,fluorine-containing alkyl, alkenyl, or aryl; each of Y and Z which maybe the same or different, is a hydrolysable group selected from halide,alkoxy or acyloxy; M is alkylene group having carbon atoms of 2 to 3;and p and q are integers of from 0 to 2).

[0015] In addition, the present invention provides an organic silicatepolymer for an interlayer insulating film for a semiconductor device,which has a carbon bridge unit in the network and is prepared by across-linking reaction between the following component (a) and (b):

[0016] (a) organosilane of the formula R¹ _(m)R² _(n)SiX_(4−m−n) (whereeach of R¹ and R² which may be the same or different, is anon-hydrolysable group selected from hydrogen, alkyl,fluorine-containing alkyl or aryl group; X is a hydrolysable groupselected from halide, alkoxy or acyloxy; and m and n are integers offrom 0 to 3 satisfying 0≦m+n≦3), or a partially hydrolyzed condensatethereof; and

[0017] (b) a cyclic silane oligomer with carbon bridge unit (Si-M-Si)(wherein, M is alkylene group having carbon atoms of 2 to 3).

[0018] Accordingly, in a first embodiment, an organic silicate polymerfor an interlayer insulating film for a semiconductor device isprovided, wherein the organic silicate polymer includes a carbon bridgeunit in a network and is prepared by a cross-linking reaction between acomponent (a) and a component (b), wherein: component (a) includes anorganosilane of the formula R¹ _(m)R² _(n)SiX_(4−m−n) wherein each of R¹and R² which may be the same or different, is a non-hydrolysable groupselected from the group consisting of hydrogen, alkyl,fluorine-containing alkyl, and aryl; X includes a hydrolysable groupselected from the group consisting of halide, alkoxy, and acyloxy; and mand n are integers of from 0 to 3 satisfying 0≦m+n≦3, or a partiallyhydrolyzed condensate thereof; and component (b) includes an organicbridged silane of the formula R³ _(p)Y_(3−p)Si-M-SiR⁴ _(q)Z_(3−q)wherein each of R¹ and R⁴ which may be the same or different, includes anon-hydrolysable group selected from the group consisting of hydrogen,alkyl, fluorine-containing alkyl, alkenyl, and aryl; each of Y and Zwhich may be the same or different, includes a hydrolysable groupselected from the group consisting of halide, alkoxy, and acyloxy; Mincludes an alkylene group including from 2 to 3 carbon atoms; and p andq are integers of from 0 to 2.

[0019] In an aspect of the first embodiment, M includes an ethylenegroup.

[0020] In an aspect of the first embodiment, the organic bridged silaneis synthesized by reacting a silane monomer containing a Si—H with asilane monomer containing an aliphatic unsaturated hydrocarbon carbongroup of formula —CH═CH₂ in the presence of a catalyst.

[0021] In an aspect of the first embodiment, the organic silicatepolymer has a weight average molecular weight of from 500 to 100,000.

[0022] In an aspect of the first embodiment, the partially hydrolyzedcondensate of the organosilane is obtained by a reaction of theorganosilane in an organic solvent after addition of water and acatalyst.

[0023] In an aspect of the first embodiment, more than 5 parts by weightof the component (b) is present per 100 parts by weight of the component(a).

[0024] In a second embodiment, an organic silicate polymer for aninterlayer insulating film for a semiconductor device is provided, whichhas a carbon bridge unit in the network and is prepared by across-linking reaction between component (a) and component (b), wherein:component (a) includes an organosilane of the formula R¹ _(m)R²_(n)SiX_(4−m−n) wherein each of R¹ and R² which may be the same ordifferent, includes a non-hydrolysable group selected from the groupconsisting of hydrogen, alkyl, fluorine-containing alkyl, and arylgroup; X includes a hydrolysable group selected from the groupconsisting of halide, alkoxy, and acyloxy; and m and n are integers offrom 0 to 3 satisfying 0≦m+n≦3, or a partially hydrolyzed condensatethereof; and component (b) includes a cyclic silane oligomer with carbonbridge unit (Si-M-Si) (wherein, M is alkylene group having carbon atomsof 2 to 3).

[0025] In an aspect of the second embodiment, M includes an ethylenegroup.

[0026] In an aspect of the second embodiment, the cyclic silane oligomerwith carbon bridge unit (Si-M-Si) is synthesized by reacting a silanemonomer containing a Si—H with a silane monomer containing aliphaticunsaturated hydrocarbon group of formula —CH═CH₂ in the presence of acatalyst.

[0027] In an aspect of the second embodiment, the cyclic silane oligomerwith carbon bridge unit (Si-M-Si) is synthesized by a hydrosilyationreaction of one or more oligomers of ring structure (I):

[0028] wherein L₁ includes an alkenyl group including 2 to three carbonatoms, and L₂ is selected from the group consisting of hydrogen, alkyl,and aryl.

[0029] In an aspect of the second embodiment, the cyclic silane oligomerwith carbon bridge unit (Si-M-Si) is synthesized by a hydrosilyationreaction of one or more oligomers of ring structure (II):

[0030] wherein M₁ includes an alkenyl group including two to threecarbon atoms, and M₂ is selected from the group consisting of hydrogen,alkyl, and aryl.

[0031] In an aspect of the second embodiment, the cyclic silane oligomerwith carbon bridge unit (Si-M-Si) is synthesized by a hydrosilyationreaction of an oligomer of ring structure (I) and an oligomer of ringstructure (II):

[0032] wherein L₁ includes an alkenyl group including two to threecarbon atoms; L₂ is selected from the group consisting of hydrogen,alkyl, and aryl; M₁ includes an alkenyl group including two to threecarbon atoms or an or allyl group including two to three carbon atoms;and M₂ is selected from the group consisting of hydrogen, alkyl, andaryl.

[0033] In an aspect of the second embodiment, the organic silicatepolymer has a weight average molecular weight of from 500 to 100,000.

[0034] In an aspect of the second embodiment, more than 5 parts byweight of the component (b) is present per 100 parts by weight of thecomponent (a).

[0035] In a third embodiment, an interlayer dielectric film for asemiconductor device is provided including the organic silicate polymerof the first embodiment.

[0036] In a fourth embodiment, a semiconductor device including theinterlayer dielectric film of the third embodiment is provided.

[0037] In a fifth embodiment, a process for preparing an interlayerdielectric film for a semiconductor device is provided, the processincluding the steps of: a) dissolving the organic silicate polymer ofclaim 1 in a solvent, whereby a dissolved solution is obtained; b) spincoating the dissolved solution obtained in step a) on a substrate toform a coating film; c) drying the coating film obtained in step b) toobtain a dried film; and d) curing the dried film obtained in step c) ata temperature of 300 to 500° C.

[0038] In a sixth embodiment, a semiconductor device including theinterlayer dielectric film prepared according to the fifth embodiment isprovided.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0039] The present invention provides a low dielectric resin compositionuseful as e.g. a resin composition capable of forming a uniformdielectric film by overcoming a drawback such that it is mechanicallybrittle, while maintaining mechanical hardness and excellent electricalproperties of a resin having a low dielectric constant.

[0040] The present invention provides a low dielectric resin compositioncomprising the following components (a) and (b), and a process for itsproduction. A dielectric film formed by the resin composition of thepresent invention is a film having a dielectric constant at most 3.3,preferably less than 3.0, wherein a cured product prepared by thecomponent (a) and component (b) are uniformly cross-linked by a chemicalreaction:

[0041] (a) organosilane of the formula R¹ _(m)R² _(n)SiX_(4−m−n) (whereeach of R¹ and R² which may be the same or different, is anon-hydrolysable group; X is a hydrolysable group; and m and n areintegers of from 0 to 3 satisfying 0≦m+n≦3) and/or a partiallyhydrolyzed condensate thereof

[0042] (b) organic bridged silane of the formula R³ _(p)Y_(3−p)Si-M-SiR⁴_(q)Z_(3−q) (where each of R³ and R⁴ which may be the same or different,is a non-hydrolysable group; each of Y and Z which may be the same ordifferent, is an hydrolysable group; M is alkylene group having carbonatoms of 2 to 3; and p and q are integers of from 0 to 2) and/or acyclic silane oligomer with organic bridge unit (Si-M-Si).

[0043] Since the resin composition of the present invention comprisesthe (a) organosilane and the (b) organic bridged silane, it hasremarkably improved crack resistance and mechanical properties, comparedto those consisting only of the (a) organosilane.

[0044] As the component (a) organosilane of the formula R¹ _(m)R²_(n)SiX_(4−m−n), each of R¹ and R² is independently hydrogen, alkyl suchas methyl, ethyl or others, fluorine-containing alkyl group such astrifluoromethyl or trifluoropropyl, or aryl such as phenyl, X isindependently hydrolysable group, halide such as chlorine, alkoxy suchas methoxy, ethoxy or propoxy, acyloxy such as acetoxy, or others. Someexamples of the component (a) organosilane include tetraalkoxysilane,mono-alkyltrialkoxysilane, dialkylalkoxysilane, tetrachlorosilane,monoalkyltrichlorosilane, dialkyldichlorosilane, a mixture thereof etc.The partially hydrolyzed product of the organosilane monomer can beobtained by allowing a monomer or an oligomer to react in an organicsolvent after addition of water and a catalyst at a temperature nothigher than the boiling point of the organic solvent for a state time.

[0045] As the component (b) organic bridged silane of the formula R³_(p)Y_(3−p)Si-M-SiR⁴ _(q)Z_(3−q), each of R³ and R⁴ is independentlyhydrogen, alkyl, such as methyl, ethyl or others, fluorine-containingalkyl group such as trifluoromethyl or trifluoropropyl, alkenyl such asvinyl or allyl, or aryl such as phenyl, Y and Z are independentlyhydrolysable group, halide such as chlorine, alkoxy such as methoxy,ethoxy or propoxy, acyloxy such as acetoxy, or others. When R³ and/or R⁴are alkenyl, it may be further bridged by a method of hydrosilylationreaction described below. Organic bridge unit, M, is alkylene grouphaving carbon atoms of 2 to 3, more preferably ethylene. If an alkylenegroup having carbon atom of 1 is used, crack resistance of the preparedresin will be deteriorated, and if one having carbon atoms more than 3is used, mechanical strength will be deteriorated.

[0046] Synthesis of the organic bridged silane is afforded fromhydrosilylation reaction, i.e. an addition reaction between a silanemonomer containing a Si—H group with a silane monomer containingaliphatic unsaturated carbon (—CH═CH₂) in presence of a catalyst or freeradical initiator. Preferred catalysts in the present invention are theplatinum group metal containing catalysts. They can be any of thoseknown in the art to effect a hydrosilylation reaction between asilicon-bonded hydrogen atom and an unsaturated carbon-carbon bond, e.g.platinum, palladium, osmium, iridium, and ruthenium etc. A transitionmetal catalyst such as platinum, or a free radical initiator is employedin an effective amount, depending on the particular catalyst used.

[0047] Cyclic oligomer with organic bridge (Si-M-Si) unit can besynthesized by the hydrosilylation reaction of a oligomer of ringstructure (I) and/or ring structure (II), i.e. an addition reactionbetween a silane monomer containing a Si—H group with a cyclic oligomer(I) and/or (II) containing aliphatic unsaturated carbon (—CH═CH₂) inpresence of a catalyst or free radical initiator,

[0048] where L₁ is alkenyl having carbon atoms of 2 to 3, and L₂ ishydrogen, alkyl such as methyl, ethyl or others, or aryl such as phenyl;and, M₁ is alkenyl having carbon atoms of 2 to 3, and M₂ is hydrogen,alkyl such as methyl, ethyl or others, or aryl such as phenyl.

[0049] The cross-linking reaction between the component (a) and thecomponent (b) may take place in the state of the solution or during thestate of forming the coating film. However, it is preferred that thecrosslinking reactions partially take place in the state of the solutionto form a uniformly distributed random copolymer. The partiallyhydrolyzed copolymer product can be obtained by allowing a component (a)and a component (b) to react in an organic solvent after addition ofwater and catalyst.

[0050] The compositional proportion of the resin (b) can be set atoptional levels depending upon the particular purpose. Usually it ispreferred to mix the organic bridged silane (b) in an amount of morethan 5 parts by weight, preferably more than 10 parts, per 100 parts byweight of the resin (a). If the proportion of the organic bridged silanecontent is too small, the mechanical properties may not be adequatelyimproved.

[0051] Solvents which may be used include any agent or mixture of agentswhich will dissolve the composition to form a homogeneous liquid mixtureof component (a) and (b). These solvents include alcohols such as methylalcohol, ethyl alcohol or isopropyl alcohol, aromatic hydrocarbon suchas benzene or toluene, ketones such as acetyl acetone, methyl isobutylketone or methyl ethyl ketone, ethers or esters, and others.

[0052] As the catalyst, an acid or a base may be used. The acid catalystis not specifically limited, and may include hydrochloric acid, sulfuricacid, phosphoric acid, nitric acid, formic acid, propionic acid, butyricacid, oxalic acid or acetic acid, succinic acid, or others. The basecatalyst is not specifically limited, and may include ammonia, organicamine, sodium hydroxide, potassium hydroxide, or others.

[0053] There are no particular limitations on the reaction temperaturewhen the product is made to have a high molecular weight.

[0054] There are no particular limitations on the reaction time at thetime of hydrolysis, and the reaction may be completed at the time theproduct reaches a stated molecular weight. It is usually preferred toset the molecular weight of the product within a range of from 500 to100,000 as a weight average molecular weight. If the molecular weight ofa hydrolyzed co-condensate of the component (a) and (b) is less than500, it may be difficult to form a uniform coating film, and if themolecular weight of a hydrolyzed co-condensate is greater than 100,000,co-condensate polymer may become insoluble. The solid contentconcentration in the solution, as the sum of the resin component (a) andresin component (b), may suitable be selected from the viewpoint of thedesired viscosity of the solution or the film thickness of the coatingfilm, within the range where the solid content dissolves.

[0055] As a method for forming a coating film on a substrate, it ispreferred to employ a method wherein the composition of the presentinvention containing a solvent is coated on the substrate, followed byheating and drying to evaporated solvent. Here the resin composition isapplied to a substrate by methods known in the art such as spin coating,dip coating, spray coating, flow coating, screen-printing or others. Thecoating method may suitably be selected depending on the shape of thesubstrate to be coated, the required film thickness, etc. When thecomposition of the present invention is to be applied to an interlayerdielectric film for a semiconductor device, a spin coating method ispreferred, since the in-plane distribution of the film thickness willthereby be uniform. The solid content concentration in the solution, asthe sum of the resin composition of (a) and (b) may suitably be selectedfrom the viewpoint of the desired viscosity of the solution or thethickness of the coating film, within the range where the solid contentdissolves.

[0056] To form a coating film, a curing step is required after coating,to evaporate the solvent and further to crosslink the partiallyhydrolyzed co-condensate of mixture of the resin component (a) and (b).The heating may be conducted as a single-step process or a step-wiseprocess. For a sufficient cure the partially hydrolyzed co-condensate ofthe mixture of resin composition (a) and (b) and to ensure thatunreacted alkoxysilyl groups or silanol groups will not remain, a finalcuring at temperature of preferably from 300 to 500° C., more preferablyfor 400 to 500° C., is required. Unreacted alkoxysilyl groups or silanolgroups will be a factor for increasing the dielectric constant of thecoating film by themselves, and they may further be a water-absorbingsite, which causes an increase of the dielectric constant by water.Accordingly, it is desirable not to let them remain in the coating film.

[0057] The coating produced by the method herein are on any substratesuch as a metal or a ceramic but particularly useful on an electronicsubstrates intended for use in manufacture of an electronic device; anintegrated circuit (IC) device, such as memory IC, logic IC or MMIC(monolithic microwave IC); a hybrid IC; a optical device, such as alight emitting diode or a charge coupled device; display device such asa liquid crystal display device and the like.

[0058] The coating film formed by the composition of the presentinvention is applied as a buffer coating film, a passivation film, or aninterlayer dielectric film for a electronic device, whereby it ispossible to attain high performance in e.g. reducing the time of signalpropagation delay of a device by virtue of excellent electricalproperties such as a low dielectric constant and a high dielectricstrength, and it is also possible to attain high reliability by virtueof excellent mechanical properties. The resin composition of the presentinvention may be useful as a matrix resin composition for preparingporous dielectric films. For instance a mixture of the resin compositionof the present invention and thermally labile polymers or organic smallmolecules may be spin-coated and thermally cured to initiatevitrification and decomposition of the labile polymers or smallmolecules.

[0059] Now, the following examples are provided to illustrate thepresent invention. The detailed preparations fall within the scope of,and serve to exemplify, the more generally described methods set forthabove. These examples are presented for illustrative purposes only, andshould not used to limit the scope of this invention found in theclaims.

EXAMPLE 1

[0060] 10 μl of 0.1 M platinum catalyst and 1.74 ml ofvinyltrimethoxysilane were mixed and reacted in a completely driedreaction container at room temperature for approximately 15 minutes, andthen 2.3 ml of trimethoxysilane was introduced therein and reaction wascontinued at 50° C. for 15 hours under a nitrogen atmosphere. Remainingreactants were completely removed under vacuum, and the completion ofthe hydrosilylation reaction was confirmed with a NMR spectrum.

[0061] 6 ml of methyltrimethoxysilane and 1.06 ml of the hydrosilylationreaction product (bistrimethoxysilylethane) were mixed in anothercontainer with 15 ml of tetrahydrofuran solvent, and the temperaturethereof was lowered to 5° C. under a nitrogen atmosphere. To the mixedsolution, 0.7 ml of 0.2 N hydrochloric acid diluted with 7.47 ml ofdistilled water were slowly added thereto while stirring. After reactionat 70° C. for overnight, the solution was cooled to room temperature,and then it was diluted with toluene and washed with distilled wateruntil the pH thereof became neutral. Magnesium sulfate was introducedinto the obtained organic layer to completely remove remaining watertherein, and the organic solvent was completely removed from theobtained organic layer in a vacuum oven.

[0062] 300 mg of the obtained powder was dissolved inmethylisobutylketone such that the total solution amounted to 1.5 g. Theobtained solution was filtered to remove impurities therefrom,spin-coated to obtain a thin film, and cured under a nitrogen atmosphereat 430° C. for 1 hour to prepare a dielectric film.

EXAMPLE 2

[0063] 10 μl of 0.1 M platinum catalyst and 1.0 ml of2,4,6,8-tetravinyl-2,4,6,8-tetramethyl siloxane were mixed and reactedin a completely dried reaction container at a room temperature forapproximately 15 minutes, and then 3.15 ml of triethoxysilane wereintroduced therein and reaction was continued at 50° C. for 15 hoursunder a nitrogen atmosphere. Remaining reactants were completely removedunder vacuum, and the completion of the reaction was confirmed with aNMR spectrum.

[0064] 40 ml of tetrahydrofuran and 19 ml of methyltrimethoxy silanewere mixed in another container and the temperature thereof was loweredto 5° C. under a nitrogen atmosphere. To the mixture solution, 20.83 mlof distilled water and 2.1 ml of 0.2 N hydrochloric acid were slowlyadded thereto while stirring. Then, the 2.1 ml of the hydrosilylationproduct was again slowly added. After reaction at 70° C. for overnight,the solution was cooled to room temperature, and then it was dilutedwith toluene and washed with water until the pH became neutral.Magnesium sulfate was introduced into the obtained organic layer tocompletely remove remaining water therein, and the organic solvent wascompletely removed from the obtained organic layer in a vacuum oven.

[0065] The obtained powder was dried and cured to prepare a dielectricfilm by the same method as in Example 1.

COMPARATIVE EXAMPLE 1

[0066] 7.6 ml of methytrimethoxysilane, 7.83 ml of distilled water and10 ml of tetrahydrofuran were mixed at room temperature, and then 0.8 mlof 0.2 N hydrochloric acid was slowly added to the mixture whilestirring. After reaction at 70° C. for overnight, the solution wascooled to room temperature, and then it was diluted with toluene andwashed with water until the pH became neutral. Magnesium sulfate wasintroduced into the obtained organic layer to completely removeremaining water therein, and the organic solvent was completely removedfrom the obtained organic layer in a vacuum oven.

[0067] The obtained powder was dried and cured to prepare a dielectricfilm by the same method as in Example 1.

[0068] Fracture properties of the films were measured using amicrovicker indenter, which can produce small cracks emanating from theindentation corners. Mechanical Young's Modulus was measured using ananoindenter (TriboIndenter from Hysitron Inc.). The results are shownin the following Table 1. TABLE 1 Comparative Example 1 Example 2Example 1 Modulus/Hardness 7.1/1.0 6.1/0.9 3.4/0.6 Crack velocity 1.1 ×10 − 11 m/s 7 × 10 − 11 m/s 6.0 × 10 − 9

EXAMPLE 3

[0069] An organic polysiloxane was prepared by the same method as inExample 1, except that 5 ml of methyltrimethoxysilane and 2.21 ml ofbistrimethoxysilyethane were used. A dielectric film was preparedtherefrom by the same method as in Example 1.

COMPARATIVE EXAMPLE 2

[0070] An organic polysiloxane was prepared by the same method as inComparative Example 1, except that 5.43 ml of methyltrimethoxysilane and2.25 ml of tetramethoxysilane were used instead of 7.6 ml ofmethyltrimethoxysilane. And, a dielectric film was prepared therefrom bythe same method as in Example 1.

[0071] Measurement of Mechanical Properties

[0072] Dielectric constant: MIS (metal/insulator/semiconductor) devicewas manufactured on a Si wafer using each of the dielectric films. Then,dielectric constant was measured using LCR meter from HP Company at 1Mhz.

[0073] Mechanical properties: The dielectric films of were respectivelyspin coated on Si wafer of 2×2 inches, and then they were cured under N2conditions at 430° C. for 1 hour. Then, mechanical properties weremeasured.

[0074] Crack resistance: Scratch tests were conducted on the films withconstant load in a horizontal direction, and the load applied when crackis generated was considered as a critical load. Spherical tip with alength of 1 μm having inside angle of 90° was used. For scratch test,critical load was measured under the conditions of film thickness ofabout 550 nm, scratch speed of 0.2 μm/sec, and loading rate of 100μN/sec.

[0075] Mechanical strength and scratch test were conducted usingTriboIndenter from Hysitron Inc.

[0076] The results are shown in the following Table 2, wherein MTMS ismethyltrimethoxysilane and BTMSE is bistrimethoxysilyethane. TABLE 2Example 3 Comparative Example 2 Composition MTMS:BTMSE = MTMS:TMOS =100:25 100:40 Dielectric constant (k) 2.93 2.91 Modulus/Hardness (GPa)9.1/1.3 9.3/1.3 Critical Load (mN) 3.75 2.91

[0077] As can be seen from the above Table 2, although the siloxaneresin of Comparative Example 2 which does not contain carbon bridgesshows good dielectric property and mechanical strength, crack resistanceis remarkably inferior to the siloxane resin of Example 3 which containscarbon bridges.

EXAMPLES 4 TO 7 AND COMPARATIVE EXAMPLES 3 TO 7

[0078] Organic polysiloxanes were prepared by the same method as inExample 1 with the compositions compositional ratios shown in the Tables2 and 3. Dielectric films were prepared therefrom by the same method asin Example 1. Mechanical properties were measured as described above,and the results were shown in the Tables 3 and 4, wherein MTMS ismethyltrimethoxysilane, BTMSE is bistrimethoxysilylethane, BTMSP isbistrimethoxysilylpropane, BTMSM is bistrimethoxysilylmethane, and BTMSHis bistrimethoxysilylhexane. TABLE 3 Comparative Comparative Example 4Example 5 Example 3 Example 4 composition MTMS:BTMSE MTMS:BTMSPMTMS:BTMSM MTMS:BTMSH (C = 2) (C = 3) (C = 1) (C = 6) 100:11 100:11100:11 100:11 (mole ratio) (mole ratio) Dielectric 2.76 2.73 2.78 2.72constant(k) Modulus/Hardness 7.1/1.0 6.4/1.0 6.8/0.9 3.8/0.6 (GPa)Critical Load(mN) 3.59 3.51 2.32 4.14

[0079] TABLE 4 Comparative Comparative Comparative Example 6 Example 7Example 5 Example 6 Example 7 Composition MTMS:BTMSE MTMS:BTMSEMTMS:BTMSH MTMS:BTMSH MTMS:BTMSH (C = 2) (C = 2) (C = 6) (C = 6) (C = 6)100:5 100:25 100:5 100:18 100:25 E/H(GPa) 5.4/0.8 9.1/1.3 4.8/0.73.8/0.5 3.7/0.5

[0080] Tables 3 and 4 show mechanical properties according to the kindsof carbon bridge units. As can be seen from Table 2, in case a carbonbridge unit is methane (C=1), mechanical strength property is similar ora little inferior, but crack resistance is remarkably inferior comparedto ethane (C=2). And, in case a carbon bridge unit is hexane (C=6),crack resistance is improved but mechanical strength is remarkablyinferior. In addition, as can be seen from Table 4, in case a carbonbridge unit is ethane, crack resistance and mechanical strength increaseas the content increases, but in the case of hexane, crack resistanceand mechanical strength decrease as the content increase. Accordingly,it can be confirmed that carbon bridge unit has suitably has carbonatoms of 2 to 3 in terms of mechanical strength and crack resistance,and more preferably has carbon atoms of 2.

COMPARATIVE EXAMPLE 8

[0081] An organic polysiloxane was prepared by the same method as inExample 1, except that only 6.36 ml of bistrimethoxysilylethane wasused. A film was prepared therefrom by the same method as in Example 1.Dielectric constant of the prepared film was measured to be 3.87, whichis very high. Therefore, it can be seen that in case a film was preparedusing a siloxane polymer consisting only of organic bridge silanecompounds, it has very high dielectric constant hence is not suitablefor a dielectric material.

[0082] The present invention solves the defects of the prior art thatconventional organic silicate film has low crack resistance andmechanical strength, by preparing an organic silicate polymer having aflexible organic bridge unit in the network. Although this invention hasbeen described with respect to specific embodiments, the details thereofare not be constructed as limitations for it will be apparent thatvarious embodiments, changes, and modifications may be resorted towithout departing from the spirit and scope thereof, and it isunderstood that such equivalent embodiments are intended to be includedwithin the scope of this invention.

What is claimed is:
 1. An organic silicate polymer for an interlayerinsulating film for a semiconductor device, wherein the organic silicatepolymer comprises a carbon bridge unit in a network and is prepared by across-linking reaction between a component (a) and a component (b),wherein: component (a) comprises an organosilane of the formula R¹_(m)R² _(n)SiX_(4−m−n) wherein each of R¹ and R² which may be the sameor different, is a non-hydrolysable group selected from the groupconsisting of hydrogen, alkyl, fluorine-containing alkyl, and aryl; Xcomprises a hydrolysable group selected from the group consisting ofhalide, alkoxy, and acyloxy; and m and n are integers of from 0 to 3satisfying 0≦m+n≦3, or a partially hydrolyzed condensate thereof; andcomponent (b) comprises an organic bridged silane of the formula R³_(p)Y_(3−p)Si-M-SiR⁴ _(q)Z_(3−q) wherein each of R¹ and R⁴ which may bethe same or different, comprises a non-hydrolysable group selected fromthe group consisting of hydrogen, alkyl, fluorine-containing alkyl,alkenyl, and aryl; each of Y and Z which may be the same or different,comprises a hydrolysable group selected from the group consisting ofhalide, alkoxy, and acyloxy; M comprises an alkylene group comprisingfrom two to three carbon atoms; and p and q are integers of from 0 to 2.2. The organic silicate polymer according to claim 1, wherein Mcomprises an ethylene group.
 3. The organic silicate polymer accordingto claim 1, wherein the organic bridged silane is synthesized byreacting a silane monomer comprising a Si—H with a silane monomercomprising an aliphatic unsaturated hydrocarbon carbon group of formula—CH═CH₂ in the presence of a catalyst.
 4. The organic silicate polymeraccording to claim 1, wherein the organic silicate polymer has a weightaverage molecular weight of from 500 to 100,000.
 5. The organic silicatepolymer according to claim 1, wherein the partially hydrolyzedcondensate of the organosilane is obtained by a reaction of theorganosilane in an organic solvent after addition of water and acatalyst.
 6. The organic silicate polymer according to claim 1, whereinmore than 5 parts by weight of the component (b) is present per 100parts by weight of the component (a).
 7. An organic silicate polymer foran interlayer insulating film for a semiconductor device, which has acarbon bridge unit in the network and is prepared by a cross-linkingreaction between component (a) and component (b), wherein: component (a)comprises an organosilane of the formula R¹ _(m)R² _(n)SiX_(4−m−n)wherein each of R¹ and R² which may be the same or different, comprisesa non-hydrolysable group selected from the group consisting of hydrogen,alkyl, fluorine-containing alkyl, and aryl group; X comprises ahydrolysable group selected from the group consisting of halide, alkoxy,and acyloxy; and m and n are integers of from 0 to 3 satisfying 0≦m+n≦3,or a partially hydrolyzed condensate thereof; and component (b)comprises a cyclic silane oligomer comprising a carbon bridge unit(Si-M-Si) wherein M comprises an alkylene group comprising from two tothree carbon atoms.
 8. The organic silicate polymer according to claim7, wherein M comprises an ethylene group.
 9. The organic silicatepolymer according to claim 7, wherein the cyclic silane oligomercomprising a carbon bridge unit (Si-M-Si) is synthesized by reacting asilane monomer containing a Si—H with a silane monomer containingaliphatic unsaturated hydrocarbon group of formula —CH═CH₂ in thepresence of a catalyst.
 10. The organic silicate polymer according toclaim 9, wherein the cyclic silane oligomer comprising a carbon bridgeunit (Si-M-Si) is synthesized by a hydrosilyation reaction of one ormore oligomers of ring structure (I):

wherein L₁ comprises an alkenyl group comprising 2 to three carbonatoms, and L₂ is selected from the group consisting of hydrogen, alkyl,and aryl.
 11. The organic silicate polymer according to claim 9, whereinthe cyclic silane oligomer comprising a carbon bridge unit (Si-M-Si) issynthesized by a hydrosilyation reaction of one or more oligomers ofring structure (II):

wherein M₁ comprises an alkenyl group comprising two to three carbonatoms, and M₂ is selected from the group consisting of hydrogen, alkyl,and aryl.
 12. The organic silicate polymer according to claim 9, whereinthe cyclic silane oligomer with carbon bridge unit (Si-M-Si) issynthesized by a hydrosilyation reaction of an oligomer of ringstructure (I) and an oligomer of ring structure (II):

wherein L₁ comprises an alkenyl group comprising two to three carbonatoms; L₂ is selected from the group consisting of hydrogen, alkyl, andaryl; M₁ comprises an alkenyl group comprising two to three carbon atomsor an or allyl group comprising two to three carbon atoms; and M₂ isselected from the group consisting of hydrogen, alkyl, and aryl.
 13. Theorganic silicate polymer according to claim 7, wherein the organicsilicate polymer has a weight average molecular weight of from 500 to100,000.
 14. The organic silicate polymer according to claim 7, whereinmore than 5 parts by weight of the component (b) is present per 100parts by weight of the component (a).
 15. An interlayer dielectric filmfor a semiconductor device comprising the organic silicate polymer ofclaim
 1. 16. An interlayer dielectric film for a semiconductor devicecomprising the organic silicate polymer of claim
 7. 17. A semiconductordevice comprising the interlayer dielectric film of claim
 15. 18. Asemiconductor device comprising the interlayer dielectric film of claim16.
 19. A process for preparing an interlayer dielectric film for asemiconductor device comprising the steps of: a) dissolving the organicsilicate polymer of claim 1 in a solvent, whereby a dissolved solutionis obtained; b) spin coating the dissolved solution obtained in step a)on a substrate to form a coating film; c) drying the coating filmobtained in step b) to obtain a dried film; and d) curing the dried filmobtained in step c) at a temperature of 300 to 500° C.
 20. Asemiconductor device comprising the interlayer dielectric film preparedaccording to the process of claim 19.